When it cannot be inferred from other layers in a larger net, the option "Input"->{d1,d2,d3} can be used to fix the input dimensions of DeconvolutionLayer.

Given an input tensor of dimensions d1×d2×d3, the output tensor will be of dimensions ××, where the channel dimension =n and the sizes d2 and d3 are transformed according to =s(di-1)+k-2p, where is the padding size, is the kernel size, and is the stride size for each dimension.